In the open field, social isolation altered locomotor activity depending on handling condition, as assessed by the number of line crossings (Interaction effect: F1,28 = 6.21, P = 0.019; η2 = 0.163; Fig. 1c). In non-handled rats, isolates exhibited more line crossings than group-reared rats (P < 0.05; Fig. 1c); this effect was absent in handled isolates (P > 0.05; Fig. 1c). In the elevated plus maze, non-handled isolates exhibited lower % open arm time compared to group-reared rats (t14 = 5.41, P = 0.000; Fig. 1d), but handled isolates were no different from group-reared rats on these measures (P > 0.05; Fig. 1d). In the prepulse inhibition test, social isolation altered % PPI in a manner dependent upon handling treatment (Interaction effect: F1,28 = 4.77, P = 0.034; η2 = 0.051; Fig. 1e). Non-handled isolates exhibited the greatest reduction in % PPI compared to all other groups (P < 0.05; Fig. 1e). Handling isolates slightly elevated, but did not restore % PPI to levels observed in group-reared rats (P > 0.05; Fig. 1e).
